JP3974666B2 - Corrosion resistant fume tube - Google Patents

Description

【００１３】
【表２】

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a corrosion-resistant fume tube, and more particularly to a fume tube having corrosion resistance against sulfur-oxidizing bacteria such as Thiobacillus sp. In a sewage treatment facility.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, it is known that concrete or mortar structures such as fume pipes generated by hydrogen sulfide or sulfuric acid generated from a sewage treatment facility or the like are plastered or deteriorated due to peeling of paint. As a cause of such deterioration, it is known that the thiobacillus sulfur-oxidizing bacteria generally present in soil and water oxidize hydrogen sulfide to produce sulfuric acid, thereby causing corrosion of the structural components. That is, the formation of sulfides in sewage is mainly caused by biochemical reduction of inorganic sulfur compounds. Many bacteria reduce sulfates to sulfides, but sulfate-reducing bacteria, especially Desulfovibrio desulfuricans , produce hydrogen sulfide from sulfates and organics in sewage. The generated hydrogen sulfide diffuses into the atmosphere and is oxidized to sulfuric acid by Thiobacillus concretivorus, a thiobacillus sulfur-oxidizing bacterium that lives on the concrete surface. These microorganisms have a very strong resistance to a low pH, and retain their activity even when the sulfuric acid concentration reaches 7%. As a result, the neutralization of concrete or mortar is promoted by sulfuric acid, and corrosion occurs.
Various proposals have been made as methods for preventing this deterioration, but an economical and effective method is not disclosed. Attempts have been made to apply drugs that exhibit antibacterial activity against sulfur-oxidizing bacteria of the genus Thiobacillus to the Hume tube. Examples of antibacterial agents include organic drugs such as cycloheximide and thiabendazole, poorly water-soluble metals, and metal oxide particles (Japanese Patent Laid-Open No. 4-149053), but are insufficient in terms of effectiveness and sustainability of antibacterial performance Met.
[0003]
[Problems to be solved by the invention]
The object of the present invention is to prevent the oxidation of sulfur produced by the proliferation of sulfur-oxidizing bacteria such as sulfate-reducing bacteria and thiobacillus in sewage pipes over a long period of time, and to prevent corrosion and deterioration. To provide a sex fume tube.
[0004]
[Means for Solving the Problems]
The present invention provides a corrosion-resistant fume tube characterized by containing an inorganic powder carrying antibacterial metal ions in a fume tube made of concrete, mortar, or a polymer material. The fume tube of the present invention maintains corrosion resistance for a long period of time.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, it is preferable that the inorganic powder supporting the antibacterial metal ions uses metal ions having stronger antibacterial performance against sulfur-oxidizing bacteria such as sulfur-reducing bacteria and thiobacillus than metal and metal oxides. However, metal ions are very unstable, and even if mixed with concrete, mortar, or polymer materials as they are, chemical changes occur immediately, and effective antibacterial action cannot be expected. For this reason, various inorganic powders are used as carriers for the metal ions as carriers that stably hold the metal ions. As these inorganic powders, materials capable of stably holding various metal ions by ion exchange can be used. For example, silica gel (SiO ₂ · nH ₂ O), hydrous alumina (Al ₂ O ₃ · nH ₂ O), hydrous titanium oxide (TiO ₂ · nH ₂ O), hydrous zirconium oxide (ZrO ₂ · nH ₂ O), hydrous Hydrous oxides such as manganese oxide (MnO ₂ · nH ₂ O), hydrous antimony (Sb ₂ O ₅ · nH ₂ O), titanium phosphate (Ti (HPO ₄ ) ₂ · nH ₂ O), zirconium phosphate ( Phosphate such as Zr (HPO ₄ ) ₂ · nH ₂ O), titanium antimonate (TiO ₂ · mSb ₂ O ₅ · nH ₂ O), tin antimonate (SnO ₂ · lSb ₂ O ₅ · nH ₂ O) Examples thereof include antimonates such as zeolite, aluminosilicates such as zeolite, clay minerals such as kaolinite and montmorillonite, hydroxyapatite, and heteropolyacid. Among these, an aluminosilicate having a high hydrous oxide, a phosphate, and a silicon content (SiO ₂ content of 60% or more) is preferable because of its high acid resistance and good corrosion resistance.
[0006]
Examples of antibacterial metal ions used in the present invention include silver, copper, zinc, nickel, cobalt, mercury, cadmium, lead, tin, palladium, rhodium, and molybdenum ions. Among these, silver, copper, zinc, nickel, and cobalt ions that have strong antibacterial performance against the genus Thiobacillus and that can be added in a relatively small amount to the fume tube are preferred.
The amount of the antibacterial metal ion supported on the inorganic powder is 0.5 to 20.0% by weight based on the amount of one or more metal ions for silver, copper, zinc, nickel and cobalt ions. As for each ion of mercury, cadmium, lead, tin, palladium, rhodium, and molybdenum, 5 to 40% by weight is appropriate for the amount of one or more metal ions.
[0007]
The particle size of the inorganic powder is preferably fine powder so that it can be easily and uniformly mixed with concrete, mortar and polymer materials. Particularly, the fine particle size is 0.001 to 0.1 mm. A powder is preferred.
The amount of the inorganic powder carrying antibacterial metal ions added to concrete, mortar or polymer material is preferably 1 to 50% by weight, more preferably 3 to 10% by weight.
In the present invention, examples of the material for forming the fume tube include conventionally known concrete, mortar, and polymer materials, and any material can be applied. Examples of the polymer material include polyvinyl chloride, epoxy resin, unsaturated polyester resin, polyethylene, and polypropylene. In forming the fume tube, naphthalenesulfonic acid / formaldehyde condensate, acrylate, methacrylate and the like can be added as a water reducing agent.
[0008]
In the present invention, any conventionally known method can be used as the method for forming the fume tube. Of these, the centrifugal molding method is preferred because the inorganic powder can be blended in a high concentration in the inner wall of the fume tube. As a centrifugal molding method, for example, there is a method described in JP-A-63-60142.
The material of the fume pipe of the present invention, using concrete, mortar or polymer material containing inorganic powder supporting antibacterial metal ions, in addition to fume pipe, tank material, plate material used in sewage treatment equipment, etc. It is also possible to produce molded products of various shapes.
[0009]
【The invention's effect】
The corrosion-resistant fume tube of the present invention can prevent corrosion and deterioration due to sulfur-oxidizing bacteria generated in a sewage treatment facility over a long period of time.
[0010]
【Example】
Hereinafter, the present invention will be described in detail based on examples.
[Reference Example 1]
Preparation of hydrous titanium oxide and zirconium phosphate inorganic powder Commercially available hydrous titanium oxide (average particle size 4.2 μm) or zirconium phosphate (average particle size 1.2 μm) 1 kg, antibacterial metal for ion exchange 2 L of an aqueous solution containing ions was added, stirred at room temperature for 24 hours, and kept in an equilibrium state. After completion, the solid phase was filtered and washed with warm water until there was no excess metal ions in the solid phase. Next, the sample was heated at 110 ° C., dried and pulverized to obtain an inorganic powder. The data of the obtained sample is shown in Table 1. In addition, each solution of silver nitrate, copper nitrate, zinc nitrate, nickel nitrate, and ammonium molybdate was used as a solution for ion exchange.
[0011]
[Reference Example 2]
Preparation of aluminosilicate inorganic powder Y-type zeolite powder (Na ₂ O · Al ₂ O ₃ · 4.8SiO ₂ , SiO ₂ ratio 64%, average particle size 0.7 μm) dried at 110 ° C. for 16 hours, Amorphous aluminosilicate powder (1.8Na ₂ O · Al ₂ O ₃ · 9.2SiO ₂ , SiO ₂ ratio 72%, average particle size 3.2μm) and clinoptilolite powder (Na ₂ O, K ₂ O ) ・ Al ₂ O ₃ .10SiO ₂ , SiO ₂ ratio 76%, average particle size 0.05 mm), water is added to make a slurry of 1.3 L, then stirred and degassed, and further an appropriate amount of 0.5 N nitric acid The solution and water were added to adjust the pH to 7.0 to a total volume of 1.8L. Next, an aqueous solution of silver nitrate, copper nitrate, nickel nitrate, mercury nitrate, cadmium nitrate, lead nitrate, tin sulfate, palladium sulfate and rhodium sulfate is added for ion exchange to make a total volume of 4.8 L, and this slurry is 25 to 48 ° C. And kept in a stirring equilibrium state for 24 hours. After completion, the aluminosilicate phase was filtered and washed with warm water until there was no excess ions in the aluminosilicate phase. Next, the sample was heated at 110 ° C., dried and pulverized to obtain an inorganic powder. The data of the obtained sample is shown in Table 1.
[Examples and Comparative Examples]
Preparation of corrosion-resistant mortar specimen After adding a predetermined amount of the inorganic powder prepared in Reference Examples 1 and 2 to a mortar component consisting of 100 parts by weight of cement, 200 parts by weight of sand, and 50 parts by weight of water, the mixture is thoroughly mixed and stirred by a mortar mixer. A mortar specimen was prepared by molding to 4 × 4 × 10 cm. As a comparative example, a test specimen was also prepared in the same manner, with no inorganic powder added, copper powder with an average particle size of 0.1 mm, and a sulfur-containing antibacterial agent (Fineside A-3 manufactured by Tokyo Fine Chemical). . Table 2 shows the data of each specimen.
[Test example]
Corrosion test of mortar specimen The mortar specimen thus obtained was exposed to the air in the sludge facility of a sewage treatment plant. After enforcement, after exposure to sludge for 6 months, 4 cm edge was cut out, and the deterioration state was examined by visually measuring the defect area when the surface of the specimen was divided into 1 × 1 mm mesh. The results of the defect area are shown in Table 2. At the same time, the surface of the specimen was washed with 50 ml of sterilized phosphate buffer with a toothbrushing brush, and the number of bacteria in the washing solution was measured using a solid ONM medium. The culture was performed at 30 ° C. for 10 days. A solid ONM medium having the following composition was used.
(NH ₄ ) ₂ SO ₄ 2.0 g
CaCl ₂・ 2H ₂ O 0.3g
FeSO ₄・ 7H ₂ O 0.01g
KH ₂ PO ₄ 4.0g
MgSO ₄ · 7H ₂ O 0.3g
Na ₂ S ₂ O ₃・ 5H ₂ O 40.0g
Bromophenol blue 0.002 g
Agar 15.0g
1L of purified water
[0012]
[Table 1]

[0013]
[Table 2]

Claims (2)

In corrosion-resistant fume pipes for sewage treatment facilities made of concrete, mortar or polymer materials,
Contains inorganic powder carrying antibacterial metal ions,
The inorganic powder is hydrous alumina, hydrous titanium oxide, hydrous zirconium oxide, hydrous manganese oxide, hydrous antimony, titanium phosphate, zirconium phosphate, titanium antimonate, tin antimonate, and aluminosilicate having a SiO ₂ content of 60% or more. At least one selected from the group consisting of salts ;
The antibacterial metal ion is one or more metal ions selected from the group consisting of silver, copper, zinc, nickel and cobalt;
The amount of the antibacterial metal ion in the inorganic powder is 0.5 to 20.0% by weight,
The corrosion-resistant fume tube , wherein the inorganic powder supporting the antibacterial metal ions is added in an amount of 1 to 50% by weight with respect to concrete, mortar or polymer material . Inorganic powder is hydrated alumina, hydrated titanium oxide, titanium phosphate, and at least one a corrosion-resistant fume tube according to claim 1, wherein is selected from the group consisting of SiO ₂ content of more than 60% of aluminosilicate.